A battery terminal type I never saw before

[burnout]

I've just been confronted by a battery terminal that looks like a small green plastic 'hat' with a serrated brim and a pair of projections like a wingnut. I've never seen one like this before. The text on it seems to just identify it as patented.

It's on a Xsara Picasso, 2000 vintage. The positive terminal is a simple snap fastening type, and it moves freely.

The negative terminal area is quite corroded, with the copper of the earth lead being covered in bluish-green crystals.

Before I try to force the old negative terminal off, can somebody tell me... what am I supposed to be doing with it? Unscrewing it I suppose? Or prising it off? It's damned stiff. And... is there anything I can use to increase the chances of releasing the old battery without destroying the terminal?

 

[burnout]

OK, replying to my own question...

They unscrew, anticlockwise as normal. Only they don't unscrew when cathodic corrosion of the battery's post terminal has left you with a bright blue mess.

Boiling water, poured over the crystallised verdigris stuff, shifted the worst of it. Then the 'wings' of the green plastic thingy were tapped gently with a small hammer, rotating it and causing it to unscrew.

Lots of small pieces of the green plastic snapped off. It was very brittle, and ultimately the whole thing jammed and had to be destroyed to get it off. But I can see that a younger specimen, properly protected with vaseline, might be unscrewed.

I'm now fitting a replacement battery terminal. One of those ordinary, machined brass ones.

 

[^neo^]

Citroen have been using them for donkeys years, get them on peugeots too.

Never understood why though really? Suppose if the car is in a accident its easy to whip it off without any tools

 

[hi1]

Is there not a threaded ring which fits over the battery terminal which has lugs that bite into and grip the lead. The thread is then pointing upwards and the cap screws to this. Sometimes this ring splits or becomes cocked which can cause the cap to stick. On my renault the rings are different sizes for +ve and -ve terminals.

 

[Stivino]

They're common on all French cars. The bits that grip the battery terminals (threaded rings) just prise off although sometimes they can be tight.

 

[TicklyT]

On the ones I've seen, the earth strap was loosely crimped to the plastic disc, so unscrewing it a couple of turns lifted the lead off the terminal and isolated the battery.

They grip the terminal post like an inverted rawlbolt. The bolt pulls a tapered cup down over the inner, clamping the inner onto the post. Prise the cup up, and they fall off, but pulling on the bolt gets you nowhere.